Long term parking at Reus Airport

Does anyone know where we can leave our car for a month or so at a time when we fly out from Reus Airport.  We used to leave it there free of charge (along with loads of other Brits, Germans etc), but now Reus charge for parking and do not have any long term parking facilities.  Does anyone know of any off-site parking or long term parking facilities not too far from the airport. 

We've been looking since parking charges were introduced but without any luck.  We now leave our car in our garage take the train to Valencia and fly to and from there instead.